CN2232639Y

CN2232639Y - Reduced voltage starter of three-phase electric motor

Info

Publication number: CN2232639Y
Application number: CN 95203260
Authority: CN
Inventors: 余炎坑
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-02-24
Filing date: 1995-02-24
Publication date: 1996-08-07
Anticipated expiration: 2005-02-24

Abstract

The utility model discloses a reduced voltage starter for a three-phase electric motor. The utility model comprises two parallel branches, and a transformer, a contactor and a button are arranged on the parallel branches. The first branch is connected with the transformer, the output and the input of the transformer are respectively connected with the contactor, and the second branch is connected with the contactor. A control circuit is composed of a coil, contacts and the button; so the first branch can be switched off when the second branch is switched on. Compared with the present common-used starter of same type, the utility model has the advantages of simple circuitry, low cost, less power consumption, etc.

Description

A kind of reduced voltage starter of threephase motor

The utility model belongs to the reduced voltage starter of a kind of servicing unit of starting motor, particularly threephase motor.

The motor of larger capacity is when starting, and starting current is big, is not subjected to the heavy current impact of electric motor starting in order to make circuit, generally is the configuration reduced voltage starter.The reduced voltage starter that generally uses is all complicated at present, price is higher, power consumption is bigger.

The purpose of this utility model provides a kind of reduced voltage starter of improved threephase motor, and its circuit is simple, price is low, little power consumption.

The utility model is achieved in that a kind of reduced voltage starter of threephase motor, it is characterized in that comprising that two are connected on the parallel three phase branch road between power supply and the motor and are connected in transformer on the branch road, contactor, button, wherein first branch road is through transformer, transformer output side is through the normally opened contact of first contactor, the coil of first contactor is connected on appointing in the two-phase of first branch road, transformer input side is through the normally opened contact of second contact, arbitrary phase of coil one termination first branch road of second contactor, its other end is access to another phase of first branch road through the normally-closed contact of the 3rd contactor, second branch road is through the normally opened contact of the 3rd contactor, the coil of the 3rd contactor and its normally opened contact, the control circuit that button constitutes are connected on appointing in the two-phase of second branch road.

The operation principle of such scheme is that first branch road is a reduction voltage circuit, second branch road is the total head circuit, power by reduction voltage circuit during starting, when motor during near rated speed, by volt circuit power supply of button control gold and cut-out reduction voltage circuit, make motor total head operate as normal, the cut-out of transformer output side is in order to prevent that golden voltage source reverse pumping from going into transformer.Such scheme is only by a transformer, three contactors, buttons and simply connect and compose, and its structure is improved and be simple, and price is lower, because during the operation of motor total head, reduction voltage circuit is cut off fully, so little power consumption.

Below in conjunction with accompanying drawing the utility model is done to describe more specifically.

Fig. 1 is the conspectus of a kind of scheme of the utility model.

With reference to Fig. 1, this reduced voltage starter, feature comprises two parallel three phase branch roads 1～3 and 4～6 and be connected in autotransformer B, contactor C on the branch road that are connected between mains switch K and the motor D ₁～C ₃, button AN, wherein first branch road 1～3 is through transformer B, and first branch road of the output side of transformer B is through the first contactor C ₁Normally opened contact C ₁, the coil C of first contactor ₁Be connected on 1,2 of first branch road and go up mutually, first branch road 1～3 of the input side of transformer B is through the normally opened contact C of second contactor ₂, the coil C of second contactor ₂2 phases of one termination first branch road, its other end is through the 3rd contactor C ₃Normally-closed contact C _3-3Be access to 3 phases of first branch road, second branch road 4～6 is through the normally opened contact C of the 3rd contactor _3-1, the coil C of the 3rd contactor ₃With its normally opened contact C _3-2, button AN constitutes control circuit and is connected on 5,6 of second branch road and goes up mutually.

During use, as Closing Switch K, contactor C ₂Get electric closure, power supply is through transformer B, contactor C then ₁Get electric closure, voltage dropping power supply input motor D after electric motor starting reaches rated speed, presses the button AN, at this moment contactor C ₃Must be electric, its contact C _3-1～C _3-2Closure, the total head power supply is made normal operation, contact C simultaneously through second branch road, 4～6 input motor D _3-3Disconnect contactor C ₂Dead electricity is cut off transformer B input, and reduction voltage circuit is not worked, simultaneously contactor C ₁Dead electricity is cut off transformer B output, goes into transformer B to prevent the total head power supply through the second branch road reverse pumping, when wanting the motor D stall, can cut off K switch.

Claims

A kind of reduced voltage starter of threephase motor, it is characterized in that comprising that two are connected on the parallel three phase branch road between power supply and the motor and are connected in transformer on the branch road, contactor, button, wherein first branch road is through transformer, transformer output side is through the normally opened contact of first contactor, the coil of first contactor is connected on appointing in the two-phase of first branch road, transformer input side is through the normally opened contact of second contactor, arbitrary phase of coil one termination first branch road of second contactor, its other end is access to another phase of first branch road through the normally-closed contact of the 3rd contactor, second branch road is through the normally opened contact of the 3rd contactor, the coil of the 3rd contactor and its normally opened contact, the control circuit that button constitutes is connected on appointing in the two-phase of second branch road.